Tit-for-tat moves this week included the use of American-made ballistic missiles to strike inside Russia, and new nuclear threats from Moscow. Neither appear to have influenced the war on the ground.

In a stark warning to the West, President Putin said the attack with the intermediate-range Oreshnik missile was in retaliation for Kyiv’s use of U.S. and British longer-range missiles.

A U.S. official said Russia has a limited number of the missiles and that it cannot regularly deploy them on the battlefield.